Figure 1: Toward improved drug and chemical safety assessment without animal testing.

In work conducted as part of the US Environmental Protection Agency's ToxCast program, Kleinstreuer et al.¹ used a panel of primary human cell types to assess the toxicity of 776 environmental chemicals and failed drugs donated by pharmaceutical companies. The resulting data set of 306,240 measurements was computationally analyzed to predict pharmacological effects, off-target adverse effects and mechanisms of chemical toxicity. This work is part of a global effort to modernize human and environmental safety assessment through improved mechanistic understanding of how compounds affect human biology, in contrast to traditional methods that extrapolate from high-dose effects seen in animals.